Breast cancer is the most common cancer in women in the United States and accounts for over 46,000 deaths annually. Several reproductive and environmental factors have been associated with increased risk. More recent recognition of the importance of genetic factors has led to renewed interest in familial breast cancer as a model for studying genetic susceptibility patterns. Recognizing the need to develop scientifically and clinically innovative approaches to the epidemiology, carcinogenesis, and prevention of breast cancer, The Fox Chase Cancer Center (FCCC) has successfully competed for support to develop a formal program in breast cancer research. This program will provide the intellectual environment to foster an interdisciplinary approach to basic, clinical, prevention and control research that will translate to medical applications aimed at reducing the incidence and mortality due to breast cancer on a local, regional and national level. The purpose of this proposal is to establish within the Breast Cancer Research Program a Familial Breast Cancer Risk Registry, using the combined resources of the Fox Chase Cancer Center, Cooper Hospital University Medical Center, and the Coriell Institute for Medical Research. This registry will serve as a resource to investigate the interaction between environmental factors and genetic susceptibility. This effort is particularly relevant in view of the wealth of information beginning to emerge from the Human Genome Project, and the implications this information will have for the counseling of women at increased genetic risk for breast cancer. The specific aims of this proposal are to: l) consolidate the existing breast cancer research programs at Fox Chase Cancer Center and Cooper Hospital University Medical Center into a comprehensive Breast Cancer Risk Registry, which will combine sociodemographic data, detailed family history, medical and reproductive history information, and health behavior characteristics in a cohort of women with familial breast cancer; 2) assemble a cohort of high risk women with documented epidemiologic, biologic, genetic and sociodemographic profiles; and 3) provide access to DNA and tissue specimens, collected, stored and distributed under conditions of the highest quality control at Coriell Institute for Medical Research, from these women. This resource will serve to promote scientific exchange and to foster collaborations that may lead to advances in our understanding of breast cancer biology.